redursidae

Hi all,

This is my first time writing a build thread, but I figured I'll give it a shot and share my journey with my NB Miata. This little car has changed my life and how I see this hobby. The car went from a fun daily driver, to a fun weekend car, to a fun trackcar that goes on the road sometimes.

Let's start with how the car was when I bought it in August of 2017:

First day:



The previous owner left a host of receipts of various autocross events it was taken to. Mods were lowering springs, sway bars, intake, NB2 header, an aftermarket muffler and what seemed to be a homemade rollbar. I think the rollbar was more of a mouse trap. Someone had removed the CEL to hide an EGR/MAP sensor code, and I fell for it. Got the thing for $3800 and some oil leaks, so I didn't mind. Believe me when I say this muffler was quiet but sounded good. The large tip was just for looks haha.

At this point I just put many miles on the car. It was my daily driver for a year until I moved to New Mexico and it stayed behind for a while. I even considered selling it at this point in time. I had made no further mods, just maintenance (plugs, wires, timing belt, water pump, etc.) and my philosophy at the time was to keep it a fun daily driver.



After a year I found myself wishing I had the fun little daily driver to enjoy in the mountains, so I drove it across the country on 06/23/2019:




At this point, I had broken the engine in the Stealth being an idiot. You see, two step is not very good on some valvetrains. Improperly installing rocker arms is also not good on valvetrains. The Stealth was my weekend fun car, and now the Miata had to take that role until I rebuilt the Stealth.

I proceeded to just enjoy the little big Miata for a while, driving it after work and on weekends. I even got to park behind the one that started it all for Mazda at a cars and coffee event:




I'll end this post here and start a new one. But it was at this point that the mod bug took hold, and the build began.

Z_WAAAAAZ

Clean looking car! Looking forward to seeing the rest of the journey.

I always had the pipe dream of taking my car on a long road trip to somewhere a few states over, hitting some killer roads along the way. However, that ship might have sailed as my car is no longer super comfy to drive for more than a few hours at a time

Gee Emm

Scooter?!

That brings back memories of a sorta similar car here called Scooter, and its now-departed driver.

Keep up the good work!

redursidae

Thanks! More to come, but may need to call it done for today after the next post.

I hear you on the lack of comfort. In its current state it is tough driving this car more than 2 hours without stopping. But I still do it for a killer road trip to Colorado or through northern New Mexico every once in a while!

Oh, sorry! I hope it isn't insulting. The car is called that because my mom called it a "chivichana", a sort of cuban home made scooter, so it stuck.

redursidae

At this point it was 2020, the Miata is in New Mexico, and the mountain roads were really showing how bad the suspension was. The car was scraping the fender liners in hard corners, and sometimes felt unstable over bumps when going fast. Not to mention smacking the bump-stops was a normal occurrence. I was also seriously wanting to take it to the local track.

Out of nowhere some unfortunate events happened to a friend's NB, and he sold me his OEM hardtop at a good price:





Another friend of mine convinced me to buy what I would consider to be the component that began this build; A set of Xida coilovers. I couldn't find any pictures of them when they arrived, because I installed them that same night. I know I took one, but it's lost to the digital gods. That happened around May of 2020. From then on things progressed quickly (for my pace that is). To improve the driving experience, the car got Xida race coilovers, PacoMotorsports strong arms, a center console delete, carbon fiber Lotus seats, a lowering bracket for the driver seat, and the A/C compressor left the chat. I also put its first nice set of tires on, some Continental ExtremeContact Sports and removed a few other bits to reduce the weight some.







After that round of mods it was a hoot on the mountains and handled amazing. No longer did I have to go wide on some corners to avoid a dip, and found myself testing the limits. Friends and I penciled June 26, 2020 for a track rental and off I was....to fix some oil leaks. After some torch action on the crankshaft sprocket, a sacrificial two jaw puller, and many rounds of cussing, I was able to replace that front crank seal, the timing belt and water pump. Also at this time I did the usual things for trackday prep, like oil change, brake fluid flush, and getting psyched!







Scooter was ready, but the cat wasn't impressed.





Next up was trackdaaaaaaaay!!

redursidae

Trackday arrived, and friends and I went to Sandia Speedway. I had hundreds of hours in a racing simulator and was feeling confident. Went out on my first session under instruction of my friend, and after two hotlaps was feeling like Ayrton Senna at Donington 1993. Going through the backstraight feeling like hot stuff, blew through a braking zone, unloaded the rear and spun the car off the track. It stopped by the grace of a dirt trap. I wish I had a video of this, because I only remember a wave of dirt and dust going over the hood and into the car. But I do have pictures of the aftermath:







The only damage was to my ego, and after a pep-talk, dusting off the car and my shame I got back out to the track and started learning. It quickly became obvious that the Continental ExtremeContact Sports are not track tires, and I kept overdriving them (later I would find that I had flatspotted one!). Fast forward a few hours and I'm trying to set my fastest lap of the day. You'll want audio for this one:





I couldn't believe it. What a manus. The engine didn't sound happy and started to stumble. It cleared up after a while, and then it stalled in the pits. FAK. After making sure no rods had escaped and checking the oil dipstick for metal, I started it and it idled. I began the drive home and the car leaves me stranded every 15 minutes. I'll cut to the chase, the CAM sensor had died and somehow kept overheating. My friend drives an hour and a half to pick up the only one I found in the vicinity, then captured this picture of an idiot fixing his Miata on the interstate. The rest of the drive home was uneventful.




I spent the night researching what happens to a stock BP at 9k RPM. This one had survived, but from this point forward there was a notable oil consumption issue. Regardless, trackday was a blast, and I couldn't wait for more. The Xidas were amazing, but I could tell the suspension needed more work, and could feel a fair amount flex in the chasis. Next up I ordered some FM frame rails and butterfly braces, SADFab bronze bearings, poly bushings, Supermiata radiator, FM coolant reroute, Blackbird GT3 Rollbar, and Toyo R888R tires.



I'll speed forward a bit. Now I had a plan and vision for Scooter; it was to follow the "slow car fast" ethos, but I wanted it to be a little different, and teach me. Like most around here, I always wanted to turbo the car (I'm a Mitsubishi fanboi after all), make 200+ whp on boost, but it was around this time that I became interested in Webber carburetors and ITBs through the same friend that introduced me to Miatas, to trackdays, and to the Xidas. I'll leave this post at a progression photodump.

Z_WAAAAAZ

Might just be me but the photos aren't showing up. I wanna see the car filled up with dirt!

Money shifted my stock motor above 8k rpm a couple times too, luckily without any notable effects as it was leaking too much oil to tell if it started consuming some as well.

Seems you were progressing the car at record speed during this point in its life!

redursidae

It wasn't just you. I had removed the attachments to attempt to cleanup the thread some. The images were cached for me so I thought it was working, but turns out it wasn't ok! I just re-added them all. Try a hard refresh (CTRL+SHIFT+R) and let me know if it's working now, please.

Fireindc

iTrader: (13)

They are workin! I saw them broken this AM too, they are def back and working now.

Love the thread man! Ricardo is a great dude, an awesome tuner, and a good driver! Keep the posts comin'!

redursidae

I'm glad I'm not the only one that made the BP scream like a B18 at least once! My soul still hurts watching that video.

Glad you think so. I was struggling with motivation and confidence during this time after damaging the Stealth's engine. Luckily my car friends kept pressuring me to continue.

Sweet! I'm glad the pics are back.

Thanks Nate! That means a lot. I'll post the next steps tomorrow. MS3, another trackday, and peer pressured into doing the ITBs right after a car meet.

Gee Emm

No way, he would be chuffed to read this thread!

So that was a 5->6 change that got 4th instead? BTDT, mine survived unscathed. The over-rev probably didn't do anything if the rods survived, but if you are going to work that engine harder at least do a quick and very dirty check on them without lifting the head.. See my build thread for my method, it only compares the height of the paired pistons but better than just crossing your fingers and hoping ... these rods are weak.

Yeah, I spun on my first lap with the instructor beside me, after him showing me Race Driver 101 for three laps!! His comment was 'At least you are trying', not sure what he was actually thinking though - couple of decades later our paths crossed again, and we had a laugh about it!

redursidae

phew. I'm glad.


It was a 3->4 that found 2nd. I'll check out your method and give it a shot, but at this point the motor will be out of the car by next season to make way for a BP-6D. More on that later. I've avoided doing a compression and leak down test on the engine because I'm afraid of what I'll find, and it just kept running for years and thousands of miles later.


haha, that's awesome. It's good that you got a laugh out of it later. My friend and I still laugh about it too.

RASKAR

Nice looking car! I'm excited to see another ITB build. What brand are the ones you have? They don't look like Jenvey, BBR, or OBX.

redursidae

Thank you! These are Borla Induction Series 2000 ITBs. Previously known as TWM Induction.

redursidae

Had to go rummaging through old drives to find more pictures of this stage, so here we go.

Shiny ITBs are sitting in my table, and an MS3 is calling. I start researching how to get it all put together and running, and come to the conclusion that there is a world to learn. Fun and exciting. First I decided to install a shorty console and relocate the window switches to it. I had previously installed a set of LRB aluminum door cards as well, and deleted the radio and speakers.









Next up was the MS3 install. I won't lie, this was a pain to get installed. The instructions made it seem like it would just go in the stock location and use the stock mounting holes, but that wasn't the case. The singular motorsports mount was awesome, and with that out of the way, the car started on the first try! Nice.











I spent sometime learning TunerStudio, MegalogViewer HD, MS3 and tuning fundamentals. Some tunings later, it was off to the track again. Big thanks to my friend Kristina for running around the track taking pictures!


















This trackday went very well. I had small off-track excursions, with the worst damage being a bent butterfly brace, and the coolant hit over 230F at least once. Laptimes were ok, around 1:39 to 1:42, but the car was fun and I was revving it to 7500RPM already. The tune was a mess. The car ran and idled, but it was rich at the lower altitude, and lean at higher altitude, and had different running states between cold and heatsoaked. I won't go into too much details, just know there was a lot of work to be done but I was stoked that it had no major failures!

Right after I installed a SuperMiata radiator, FM coolant reroute, and deleted the MAF. Took the car to the local meet, and got peer pressured into starting the ITB install that day....













I didn't take many pictures of the specific modifications that had to happen to fit these, but from what I remember:
1. Bend the fuel feed line slightly to allow space for the air filter
2. Shorten and resolder throttle cable
3. Modify throttle cable adjuster (provided by Borla) to fit the Miata cable
4. Cap stock injector ports at the head
5. Modify wiring to use a new TPS and reroute other wires (e.g grounds)
6. Mount a vacuum block for the MAP signal and brake booster

After all of these mod and a modified tune, we said screw it and gave it a crank:




The damn thing started on the first try again! I was so happy. Big shoutout to my friend Richard for letting me use his shop, and helping me get these mods done. It took one week of afternoons to get the car started. Richard wasn't happy with the other side of the engine bay, so we decided to install that sexy ISR header. It took some grinding and cutting to make it fit the mid pipe, but the end result looked really cool:



I'll stop this one here. This was around June 26, 2021, and from then on began the tuning, more learning and issue discovery phase of ITBs. The next goal for Scooter was to make it to its first cars and coffee and another trackday as an ITB Miata!

Fireindc

iTrader: (13)

Awesome, that ISR header really does (did) look cool aye?

Love the pics you dug up, and love that first start video. The manic cackling is hilarious, and I love it.

redursidae

It really did look cool. Unfortunately, the craftsmanship didn't hold up, and it had a very bad resonance that travel through the car around 3600RPM, which is probably what cracked it.

Hahaha I'm glad you liked that. I was so happy when it fired and I heard those snorts for the first time!

redursidae

It's almost been a month already! So next in the saga was getting the car tuned. ITBs are very finicky, and cannot be tuned using Speed Density. Alpha-N is the only reliable way to tune an NA ITB engine so I had to learn that method. Megasquirt has a cool tuning algorithm, called ITB Mode that blends SD and AN into one table, and that allows the best of both worlds. SD while idling and cruising, and AN during higher loads! The tricky bit was to learn how to setup ITB mode, and to gather all the data I tuned the car on a Hybrid Alpha-N setup, went to a trackday and gathered a couple of hours of different load areas. Right away I could tell something was very wrong with the tune though. Idle VEs were around 88, and the car was pig rich during warmup (10 to 11AFR), and fixing warmup messed up the running at operating temperature.

A few pics of the first time I took it out on a weekend cruise:







A few pics of the first trackday. There aren't many because I spent the whole time looking through the data and learning. Something I enjoyed was watching the header change color week after week. Sorry about the dirty engine bay on these....I may have confused Scooter for a rally car during this trackday.....






All the while I was chasing my tail on the warmup issue, the idle SUCKED when cold and I had to feather the throttle when coming to a stop to keep it from stalling. If there is anything you learn from my journey is that ITBs without an Idle Valve are a PITA to live with. But for the next 6 months or so I just kept learning how to tune the damn thing, and was loving the noises.

At some point in 2022 my friend Tim pitches the idea of going to Flyin Miata summer camp. At first a trackday was mentioned, which was later changed to an autocross. I wasn't stocked on the idea of autocross, but a road trip to Colorado sounded like a great time. Just a few issues to address, my suspension bushings were looking...expired, and I couldn't stand the idle issues anymore. I also had been thinking of installing longer trumpets and see what difference they made. So Tim made me an aluminum bracket to install an NB Miata IACV, I got busy designing and 3D printing some Carbon Fiber trumpets, installing SADFab bronze bearings, new alignment and more tuning!













Unfortunately that's as much camber as the front could do. I knew I wanted more down the line and started researching extended ball joints, but that was a project for a later time. At this point I had also removed the power steering and was recommended to run that much caster to help the return to center and the steering effort was considerable but not unbearable. On the next update I'll add pictures of FMSC and the next trackday for the car!

Z_WAAAAAZ

Loving reading this thread. The and thoroughness and abundance of photos are greatly appreciated.

Have you run less than 6* of caster without power steering since the first alignment? I was never able to produce less than 4.7* with my current setup but never had an issue with steering effort. I remember being nervous at first because it seemed like the general consensus was that you should run degrees of caster or even a hair less if possible.

Excited to hopefully see the carbon trumpets on the next post!

redursidae

I'm glad you're enjoying it! I'm doing my best to find pictures in order.

Yes, I've ran less than 6* fairly recently while I was testing different alignments. I tried -3* camber and 5* caster which was nice on the street with no return to center issues, and the car was palyful. On track it oversteered and locked the front brakes fairly easy. I could have fixed that with sway bars and adjusting the brake bias, but I decided to re-align instead because the tire wear was rough and it sees 200miles of road just to get to a track. Now I run -2.56* camber and 5.5* caster which made the car neutral as I expected based on my saw bar settings (rear is set at the middle, front isn't adjustable). I can make the car oversteer if I try which is great, steering effort is still considerable but I don't mind it. I based my alignment off the supermiata specs for dual duty, and my alignment mechanic's recommendations for the caster, so far the tire wear in the last two events has been great and tire temps were good too.

The carbon fiber trumpets are in the last picture above! They're not weaved carbon like you might have expected because they're 3D printed. I used a carbon fiber polycarbonate filament from Prusa: https://www.prusa3d.com/product/prus...-black-800g-2/

Link to print: https://www.printables.com/model/453...hrottle-bodies